Fiber-to-the-curb (FTTC) systems can provide both traditional telecommunications services such as Plain Old Telephony service (POTS) as well as advanced services such as Switched Digital Video (SDV) and high speed data access. Because of the range of services which can be supported, it is likely that FTTC systems will be widely deployed by telephone companies as they install new lines and upgrade their networks.
Since POTS is the basic telephone service that is used by over 100 million subscribers in the US, it is essential that the service be reliable. FTTC equipment provides POTS service by the use of a printed circuit board containing electronics supporting one or more telephone lines, usually termed a universal voice grade (UVG) card. The UVG cards are located in a broadband network unit which is typically located in the neighborhood near a group of homes. In a widespread deployment of FTTC there will be millions of UVG cards for BNUs, and the telephone companies will maintain large inventories of these cards for installation and maintenance.
Faulty operation of a UVG card may take place due to the fact that the card has an electrical failure, or may occur due to an error in the software, including hardware programmable state machines, contained within the card. In addition, it is possible that a UVG card may be incompatible with a particular FTTC system due to design flaws or faulty manufacturing. Key aspects in the operation of the UVG card include the proper functioning of any application specific integrated circuits (ASICs) on the card, proper functioning of the state machine which controls the various states of the line including on-hook, off-hook, and ringing, as well as the ability to modify the state machine in the case of a programming error or system change, and the ability to properly test the communications channel formed by the circuit on the UVG card and the twisted pair drop cable which connects the card to the residential telephone wiring.
For the foregoing reasons there exists the need for methods and apparatus to identify the type and source of UWG cards in the FTTC system, properly test the functioning of any ASICs on the UVG card, verify state machine software and download new versions of state machine software, and test the subscriber telephone line.